Indiana Code Title 6. Taxation § 6-2.5-11-5

Sec. 5. The department may enter into the agreement with one (1) or more states to simplify and modernize sales and use tax administration in order to substantially reduce the burden of tax compliance for all sellers and for all types of commerce.  In furtherance of the agreement, the department may act jointly with other states that are members of the agreement to establish standards for certification of certified service providers and certified automated systems and to establish performance standards for multistate sellers.  The department may take other actions reasonably required to implement this chapter.  Other actions authorized by this section include, but are not limited to, the adoption of rules and the joint procurement, with other member states, of goods and services in furtherance of the cooperative agreement.  The department or the department's designee shall represent the state of Indiana before the other states that are signatories to the agreement.